The Supreme Court Unreasonably Restricts Evidence Challenging Breathalyzers

Posted by Richard Lawson | Aug 15, 2014 | 2 Comments

The DUI Exception To The Constitution is Alive And Well:

On June 23, 2014, the United States Supreme Court essentially held that a defendant accused of a DUI couldn't challenge the accuracy of breath testing machines with expert testimony.

In People v. Vangelder, the defendant was accused of driving under the influence of alcohol after a highway patrolman stopped him for driving over 125 mph. Even though the defendant displayed few clues to support this charge during the field sobriety tests, the officer administered two breath tests that registered .095 and .086 percent.

At trial, the defense attorney called an expert witness, a University of Washington Professor of Medicine and Physiology, who testified that the breath-testing machines are unreliable because they measure the content of exhaled air, which can be affected by several variables.

The California Supreme Court held that DUI suspects may not call expert witnesses to challenge the reliability of BAC tests. The court reasoned that these devices have been studied by the legislature and certified by U.S. Department of Transportation. The court maintained that this ruling does not leave a defendant without options, and the defense may argue that a particular machine was defective or was improperly used.

The defendant in People v. Vangelder was ultimately convicted of DUI and speeding, and he challenged the ruling by appealing it to the United States Supreme Court. Unfortunately, the Court refused to take up the case, thereby affirming the ruling of the California Supreme Court.

Understandably disappointed with the Court's decision, the defense attorney pointed out that it was "unduly trusting in the infallibility of government testing of these machines.” He's right. Among the several issues surrounding the reliability of these breath test machines is the fact that the manufactures refuse to release the machine's source code.  A breath test machine is essentially a computer, and the source code is the computer program that runs the machine and allows it to analyze the breath sample.

The company that manufactures the machines consistently (and conveniently) refuses access to the code, claiming that it is a “protected trade secret.”  While this claim is not without merit, judges often resolve trade secret cases by keeping the record secret. From an evidentiary standpoint, it is baffling why this procedure would not be used in a DUI case.

The source code would show the errors the machine had to resolve as well as how it actually calculates a person's B.A.C. It would also show what assumptions are made in the calculations, such as ambient temperature, radio frequency interference, and what would cause a sample to be considered an invalid sample.

This blind trust in the reliability of these machines is misplaced.  After all, if we trust their reliability so much that we will not allow an expert to challenge it; then why are there so many models of the device? Every time a newer breathalyzer model is released, the manufacturers give us reasons to question the older technology's accuracy.

In Georgia we are presently “upgrading” our breath-testing machines from the Intoxilyzer 5000 to the Intoxilylzer 9000. If the Intoxilyzer 5000 was so perfectly error-free, why invest in new machines?  I would certainly like to know what advances in breath-testing have occurred in the past 20 years causing past machines to become obsolete.

CMI, the manufacturer of the Intoxilyzer, will not allow defense attorneys to look at the code.  Their attorneys, along with attorneys from the State of Georgia, have successfully fended off all efforts to obtain this code.  And now the U.S. Supreme Court has held that these machines are “good enough for government work.”  We cannot challenge the breath-testing results because our challenges would be speculative.  Yet, the reason that we can merely speculate as to the accuracy (or lack thereof) of these machines is that we cannot access the source code for the machines.

It all comes down to the politics of DUI.  People hate DUI, and as a result, Georgia DUI defense Attorneys and their clients are vilified, even at the expense of justice.

About the Author

Richard Lawson

Managing Partner at Lawson & Berry:


Guy sharpe Reply

Posted Aug 16, 2014 at 19:41:17

The Supreme Court ruling shows that DUI defendants are not entitled to equal protection of the law. The cards are stacked against them. You are given full protection of the law if you are charged with murder, not DUI.

Leave a Comment

Georgia DUI Defense Attorneys

At the Law Office of Richard S. Lawson, we have offices conveniently located throughout metro Atlanta and throughout Georgia. If we do not have a convenient office, we will come to you. We practice throughout Metro Atlanta and North Georgia. If your case is in an area we do not serve, we will find you an attorney in your area free of charge. Our office is part of a State-wide network of Georgia DUI Lawyers. Contact us 24/7 for immediate legal help. Our attorneys are standing by. Your DUI Case will not defend itself. Your Best Georgia DUI Defense Begins Here!